NHTSA Killed a Rule That Would Prevent 1,115 Fatal Crashes a Year. Then It Threw a Party.

Every Class 8 tractor-trailer rolling down an American interstate has an engine control unit wired to a speed governor. That hardware has been standard since the early 2000s. Flipping the switch costs nothing. Werner, JB Hunt, Schneider, and most of the nation's largest carriers already cap their trucks between 62 and 68 mph voluntarily, because slower trucks burn less fuel and crash less violently. In January 2026, NHTSA and FMCSA formally withdrew the federal rule that would have required everyone else to do the same.

That number is not from a trucking lobby white paper or a safety advocacy group's estimate. It comes from NHTSA's own 2016 Preliminary Regulatory Impact Analysis, filed alongside the proposed rule in the Federal Register (81 FR 61942). Over a decade, the agencies built the case: petitions from the American Trucking Associations and Roadsafe America, thousands of public comments, a formal cost-benefit analysis that put annual costs between $209 million and $1.5 billion depending on the set speed, and a finding that virtually every affected vehicle was already equipped with the hardware. Compliance cost for trucks that already had capable ECUs was negligible.

They killed it anyway, citing "significant policy and safety concerns and continued data gaps." The withdrawal notice invoked Executive Order 14219, the DOGE deregulatory initiative, and Executive Order 14192 on rescinding regulations deemed overly burdensome. But the technical rationale leaned on a single claim: "crash avoidance technologies under development may achieve the safety goals of this rulemaking better than a speed limiter requirement."^[1]

That claim refers to automatic emergency braking for heavy trucks, proposed in a July 2023 NPRM (88 FR 43174). As of June 2026, that rule has not been finalized. No mandate exists requiring AEB on commercial vehicles over 26,000 pounds. NHTSA cited automatic emergency braking for heavy trucks as a replacement for the speed limiter, but in regulatory terms, that technology is a draft document on a shelf gathering dust while the withdrawal of the rule it was supposed to replace is already in effect, already saving nobody, already letting trucks barrel through Nevada and Texas at 85 mph with the governor wide open.^[2]

Three months after burying the speed limiter, NHTSA released its 2025 preliminary fatality data: 36,640 dead, a 6.7% decline from 2024, the second-lowest fatality rate in recorded history at 1.10 per 100 million vehicle miles traveled. Administrator Jonathan Morrison held a press conference and described the numbers as reflecting "NHTSA's close collaboration with state and local partners." Secretary Duffy credited the "Freedom Means Affordable Cars" initiative and partnerships with law enforcement, as though someone in Washington had personally willed 2,614 Americans back to life by making Corollas cheaper.^[3]

Run the math NHTSA did not run in its press release. NHTSA proposed the speed limiter rule in September 2016. Every year it sat unfinalized was a year where an estimated 1,115 fatal crashes that could have been prevented were not. From 2017 through 2025, that is nine years of regulatory paralysis on a rule requiring hardware that was already installed, at a cost the agencies themselves called negligible for most of the fleet. A conservative reading of NHTSA's own numbers puts the cumulative toll at roughly 10,035 fatal crashes that did not need to happen. Not all fatal crashes produce exactly one death, but with large-truck-involved fatalities averaging 1.1 deaths per fatal crash in FARS data, the body count approaches eleven thousand.

OOIDA fought speed limiters for years, arguing they create dangerous speed differentials between governed trucks and passenger traffic, and they are not wrong to raise the question; a 65-mph truck merging into 80-mph traffic generates exactly the kind of closing-speed collision that kills motorcyclists and compact-car drivers. FMCSA acknowledged it could not fully model these secondary effects. But NHTSA's cost-benefit analysis already incorporated speed differential crash risk and still projected net savings of 1,115 fatal crashes per year. Whether speed differentials are more dangerous than ungoverned trucks at 85 mph was the real question. NHTSA's own analysis said no. Then NHTSA's own leadership said they did not trust their own analysis enough to act on it.^[4]

What makes this withdrawal distinct from ordinary regulatory inertia is the specificity of the engineering. This was not a rulemaking requiring manufacturers to develop new technology, redesign vehicle architecture, or meet performance standards that pushed the state of the art. Speed governors exist. They work. They are already installed. Major carriers already use them. The proposed rule would have required the remaining carriers to set a number in software that is already present in every engine control unit manufactured in the last two decades. NHTSA estimated the per-vehicle compliance cost for trucks that already had capable ECUs at effectively zero dollars. What remained was a decision to let a solved problem remain unsolved because solving it had become politically inconvenient.

Meanwhile, the technology NHTSA cited as the speed limiter's replacement, AEB for heavy trucks, will not be mandatory for new vehicles until at least 2029 even if the rule is finalized tomorrow. Fleet turnover for Class 8 trucks averages 15-20 years. Full penetration of a new-vehicle mandate into the operating fleet takes roughly two decades after the manufacturing date. If AEB for heavy trucks is mandated in 2029, the fleet will not be fully equipped until the late 2040s. Speed limiters could have been active across the entire existing fleet within months of finalization, because the hardware is already there.

What You Can Do

If you drive near commercial trucks: stay out of the right lane on rural interstates, especially at night. Trucks you pass at 75+ mph may not have AEB, may not have forward collision warning, and are no longer on track to have a speed governor mandate backing them up. Closing speed between your car and a truck is the single most important variable in whether a rear-end collision is survivable. Every 10-mph increment above 65 mph roughly doubles impact energy.

If you operate a fleet: set your own governors. Werner caps at 65 mph and reports fuel savings of 6-8% and lower insurance premiums. That math has been public for years. A federal mandate mattered only for the carriers who refused to do the math voluntarily.

Limitations

The 1,115-crash estimate originates from NHTSA's 2016 PRIA, which used crash data from an era before widespread adoption of forward collision warning in heavy trucks. Voluntary AEB adoption among large fleets may have partially reduced the gap, though no updated estimate has been published. NHTSA's cumulative body count calculation (9 years × 1,115) assumes the annual estimate remained roughly constant, which is uncertain. "Fatal crashes prevented" is not identical to "deaths prevented," as multi-fatality crashes and crashes where the truck driver survives while other parties die complicate the conversion. NHTSA's cost estimates ranged by a factor of seven depending on the set speed, reflecting genuine uncertainty about the optimal limit.